Heat Capacity Effects Associated with the Hydrophobic Hydration and Interaction of Simple Solutes: A Detailed Structural and Energetical Analysis Based on MD Simulations

We examine the SPCE and TIP5P water models to study heat capacity effects associated with the hydrophobic hydration and interaction of Xenon particles. We calculate the excess chemical potential for Xenon employing the Widom particle insertion technique. The solvation enthalpy and excess heat capacity is obtained from the temperature dependence of the chemical potentials and, alternatively, directly by Ewald summation, as well as a reaction field based method. All three different approaches provide consistent results. The reaction field method allows a separation of the individual components to the heat capacity of solvation into solute/solvent and solvent/solvent parts, revealing the solvent/solvent part as the dominating contribution. A detailed spacial analysis of the heat capacity of the water molecules around a pair of Xenon particles at different separations reveals that the enhanced heat capacity of the water molecules in the bisector plane between two Xenon atoms is responsible for the maximum of the heat capacity observed at the desolvation barrier, recently reported by Shimizu and Chan ({\em J. Am. Chem. Soc.},{\bf 123}, 2083--2084 (2001)). The about 60% enlarged heat capacity of water in the concave part of the joint Xenon-Xenon hydration shell is the result of a counterplay of strengthened hydrogen bonds and an enhanced breaking of hydrogen bonds with increasing temperature. Differences between the two models concerning the heat capacity in the Xenon-Xenon contact state are attributed to the different water model bulk heat capacities, and to the different spacial extension of the structure effect introduced by the hydrophobic particles. Similarities between the different states of water in the joint Xenon-Xenon hydration shell and the properties of stretched water are discussed.Comment: 14 pages, 16 figures, twocolumn revte

Investigation of Sea-surface Microlayer and Phytoplankton Culture Samples by Monolayer Techniques and Brewster Angle Microscopy

Natural samples of sea-surface microlayer and phytoplankton culture samples have been studied by monolayer techniques and by Brewster angle microscopy (BAM). Surface pressure-area (π-A) and surface potential-area (ΔV-A) isotherms have been measured. Simultaneously BAM video images have been recorded. The π-A isotherms, as well as BAM images of monolayers of dipalmitoyl phosphatidylcholine (DPPC), dimyristoylphosphatidic acid (DMPA) and dioctadecyldimethyl ammonium bromide (DOMA) spread on an aqueous subphase containing a sample of phytoplankton culture show that surface active substances released by phytoplankton influence molecular organization as well as domain morphology of the lipid monolayers. The sea-surface microlayer sample spread at the air/water interface exhibits the characteristics of a liquid expanded phase without undergoing a phase transition. The BAM images taken from this film depend on surface pressure, showing at low surface pressures liquid condensed domains surrounded by a liquid expanded phase, and at higher surface densities only a liquid condensed phase

Investigation of Sea-surface Microlayer and Phytoplankton Culture Samples by Monolayer Techniques and Brewster Angle Microscopy

Natural samples of sea-surface microlayer and phytoplankton culture samples have been studied by monolayer techniques and by Brewster angle microscopy (BAM). Surface pressure-area (π-A) and surface potential-area (ΔV-A) isotherms have been measured. Simultaneously BAM video images have been recorded. The π-A isotherms, as well as BAM images of monolayers of dipalmitoyl phosphatidylcholine (DPPC), dimyristoylphosphatidic acid (DMPA) and dioctadecyldimethyl ammonium bromide (DOMA) spread on an aqueous subphase containing a sample of phytoplankton culture show that surface active substances released by phytoplankton influence molecular organization as well as domain morphology of the lipid monolayers. The sea-surface microlayer sample spread at the air/water interface exhibits the characteristics of a liquid expanded phase without undergoing a phase transition. The BAM images taken from this film depend on surface pressure, showing at low surface pressures liquid condensed domains surrounded by a liquid expanded phase, and at higher surface densities only a liquid condensed phase

Direct conversion of rheological compliance measurements into storage and loss moduli

We remove the need for Laplace/inverse-Laplace transformations of experimental data, by presenting a direct and straightforward mathematical procedure for obtaining frequency-dependent storage and loss moduli ($G'(\omega)$ and $G"(\omega)$ respectively), from time-dependent experimental measurements. The procedure is applicable to ordinary rheological creep (stress-step) measurements, as well as all microrheological techniques, whether they access a Brownian mean-square displacement, or a forced compliance. Data can be substituted directly into our simple formula, thus eliminating traditional fitting and smoothing procedures that disguise relevant experimental noise.Comment: 4 page

EEG analysis based on dynamic visual stimuli: best practices in analysis of sign language data

This paper reviews best practices for experimental design and analysis for sign language research using neurophysiological methods, such as electroencephalography (EEG) and other methods with high temporal resolution, as well as identifies methodological challenges in neurophysiological research on natural sign language processing. In particular, we outline the considerations for generating linguistically and physically well-controlled stimuli accounting for 1) the layering of manual and non-manual information at different timescales, 2) possible unknown linguistic and non-linguistic visual cues that can affect processing, 3) variability across linguistic stimuli, and 4) predictive processing. Two specific concerns with regard to the analysis and interpretation of observed event related potential (ERP) effects for dynamic stimuli are discussed in detail. First, we discuss the “trigger/effect assignment problem”, which describes the difficulty of determining the time point for calculating ERPs. This issue is related to the problem of determining the onset of a critical sign (i.e., stimulus onset time), and the lack of clarity as to how the border between lexical (sign) and transitional movement (motion trajectory between individual signs) should be defined. Second, we discuss possible differences in the dynamics within signing that might influence ERP patterns and should be controlled for when creating natural sign language material for ERP studies. In addition, we outline alternative approaches to EEG data analyses for natural signing stimuli, such as the timestamping of continuous EEG with trigger markers for each potentially relevant cue in dynamic stimuli. Throughout the discussion, we present empirical evidence for the need to account for dynamic, multi-channel, and multi-timescale visual signal that characterizes sign languages in order to ensure the ecological validity of neurophysiological research in sign languages

Linear Compressor Discharge Manifold Design For High Thermal Efficiency

In the design of hermetic compressors for household refrigeration, one important part of the overall efficiency of the machine comes from a good thermal efficiency of the discharge manifold. It is desired that the heat generated during the compression process and accumulated by the gas in the discharge chamber does not return to the compression chamber walls. If not, this heat returns to the pump, reducing volumetric efficiency. Current technologies like on/off and variable velocity compressors, normally make use of metallic parts in the discharge chamber, such parts having high thermal conduction coefficients making them less efficient. Linear compressor technology, together with the non-use of oil allows the improvement of the discharge manifold system, increasing the thermal insulation of the heat from discharge chamber to compression chamber, improving efficiency. This article aims to show the development of this improved discharge system, tests performed, and results obtained

Visual boundaries in sign motion: processing with and without lip-reading cues

Sign languages demonstrate a higher degree of iconicity than spoken languages. Studies on a number of unrelated sign languages show that the event structure of verb signs is reflected in the phonological form of the signs (Wilbur (2008), Malaia & Wilbur (2012), Krebs et al. (2021)). Previous research showed that hearing non-signers (with no prior exposure to sign language) can use the iconicity inherent in the visual dynamics of a verb sign to correctly identify its event structure (telic vs. atelic). In two EEG experiments, hearing non-signers were presented with telic and atelic verb signs unfamiliar to them, which they had to classify in a two-choice lexical decision task in their native language. The first experiment assessed the timeline of neural processing mechanisms in non-signers processing telic/atelic signs without access to lip-reading cues in their native language, to understand the pathways for incorporation of physical perceptual motion features into linguistic processing. The second experiment further probed the impact of visual information provided by lip-reading (speech decoding based on visual information from the face of the speaker, most importantly, the lips) on the processing of telic/atelic signs in non-signers

Междометные фразеологизмы с компонентом зоонимом в английском, казахском и русском языках: эмоциональное и оценочное содержание

Цель – определение общих и специфических характеристик предмета исследования с вытекающими задачами сопоставительного ступенчатого описания избранных МФЕ, выражающих базовые эмоции (радость, гнев, печаль и др.) и их разновидности

Linear Compressor Suction Valve Optimization

Design of hermetic compressors for household refrigeration follows a common sequence that considers an initial concept, normally based on existing families. Those are then upgraded with new features, aiming improvements in efficiency, sound quality or even cost reduction. Common compressors have a cylinder head that carries discharge and suction valve. In a new and compact designs for linear compressor suction valve is placed on the top of the piston, requiring new shapes in order to make it possible to satisfy, gas flow, fatigue and dynamics requirements. This article aims to present the use of optimization procedure used to develop the suction valve design for a linear compressor, the results obtained with the optimization process, and final results in compressor, in terms of performance and noise

How to measure patent thickets – a novel approach

The existing literature identifies patent thickets indirectly. In this paper we propose a novel measure based on patent citations which allows us to measure the density of patent thickets directly. We discuss the algorithm which generates the measure and present descriptive results validating it. Moreover, we identify technology areas which are particularly impacted by patent thickets